scholarly journals Natural convective heat transfer from a heated horizontal elliptical cylinder to its coaxial square enclosure

2018 ◽  
Vol 5 (4) ◽  
pp. 379-385
Author(s):  
Abdelkarim Bouras ◽  
Djedid Taloub ◽  
Mahfoud Djezzar ◽  
Zied Driss
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Elliptical Cylinder ◽  
Square Enclosure

Numerical Study of Convective Heat Transfer of Multiple Internal Isolated Blocks in an Enclosure

Solar Energy ◽  
2005 ◽  
Author(s):  
Xutao Zhang ◽  
Jianing Zhao ◽  
Fusheng Gao ◽  
Jun Gao ◽  
Songling Wang
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Convective Heat Transfer ◽  
Forced Convection ◽  
Convective Heat ◽  
Numerical Study ◽  
Thermal Design ◽  
Square Enclosure ◽  
Forced Convective Heat Transfer ◽  
Low Reynolds

The treatment of Convective Heat Transfer Coefficients (CHTCs) in an enclosure has a significant impact on the thermal design of electronic appliance, especially the CHTCs in an enclosure with internal isolated blocks. The CHTCs of the isolated blocks for pure natural convection are usually used, while it may not be applicable to any practice. Combined convective heat transfer, even forced convective heat transfer, is sometime more applicable in reality. In our present work, first of all, validation of the turbulence model for CFD simulation of natural convective flows in a square enclosure is performed. The values of CHTCs for vertical walls obtained by using a low Reynolds k-ε model agree well with the existed correlations. The simulation also indicates that the distance from the first grid to the wall has a significant impact on the CHTCs. Using this low Reynolds k-ε model, computer simulations of natural and forced convective heat transfer within a square enclosure containing ten isolated blocks are performed. For both the natural and forced convection, the dimensionless Nusselt numbers are derived by the obtained results. For the case of mixed convection, the CHTCs are established by blending those for natural and forced convection using the Churchill-Usagi approach, which is a general expression combines the asymptotic solutions of independent CHTCs into the mixed convection by using a Churchill-Usagi blending coefficient.

scholarly journals The Natural Convective Heat Transfer in a Partially Divided Enclosure: A Study on the Influence of the Source Position

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Francesco Corvaro ◽  
Massimo Paroncini
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Dynamic Behaviour ◽  
Velocity Fields ◽  
Source Position ◽  
Square Enclosure ◽  
Nusselt Numbers ◽  
First Case ◽  
Rayleigh Numbers

The aim of this paper is to analyse the natural convective heat transfer generated by a source with a height of located in two different positions inside a square enclosure of side . In the first case, is 0.5 of while in the second case it is 0.4. The comparison is based both on the evaluation of the local and average Nusselt numbers at different Rayleigh numbers and on the study of the velocity fields at the same Rayleigh numbers in the two different configurations. The experimental analysis was carried out through a holographic interferometry, to study the heat transfer, and through a 2D-PIV system, to analyse the dynamic behaviour of the phenomenon. Finally, for = 0.5 we compared the experimental results with those obtained through the volume finite software Fluent 6.3.26. In the analysis, it is possible to see that the position of the source influences both the average Nusselt numbers on the hot surfaces and the development of a small bubble on the upper surface.

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